Pyrgulopsis intermedia ( Tryon, 1865 )

Hershler, Robert & Liu, Hsiu-Ping, 2009, New species and records of Pyrgulopsis (Gastropoda: Hydrobiidae) from the Snake River basin, southeastern Oregon: further delineation of a highly imperiled fauna, Zootaxa 2006, pp. 1-22 : 19-20

Pyrgulopsis intermedia ( Tryon, 1865)

( Figs 10–11 )

Pomatiopsis intermedia Tryon, 1865: 220 [type locality, Owyhee R., S. E. Oregon; original label states Crooked Creek, Owyhee, southeast Oregon].

Pyrgulopsis intermedia ( Tryon, 1865) .— Hershler 1994: 42, 44, figs 17a–d, 36c, 47b (synonymy, diagnosis, description).

Referred material. OREGON. Malheur County. JFBM 20497, JFBM 20507, Crooked Creek Spring, ca. 16 km southwest of Burns Junction, T. 33 S, R. 39 E, sec. 22, 23/v/1963, 19/v/1982. USNM 1075362, spring tributary to Birch Creek, 459964 E, 4781865 N, 25/iv/2003. USNM 1075684, ibid., 459871 E, 4782621 N, 25/vi/2003. USNM 1092855, ibid., 460058 E, 4781808 N, 18/vii/2006. USNM 1107071, spring on east side Owyhee River, above Long Sweetwater rapids, 442355 E, 4753770 N, 6/ix/2007. USNM 1107076, spring on hillside, Jackson Hole, 447566 E, 4781838 N, 8/ix/2007. USNM 1107079, spring west of Two Mile Spring, 453320 E, 4782496 N, 9/ix/2007. USNM 1107077, mouth of Rinehart Creek, west side of Owyhee River, 449007 E, 4783611 N, 9/ix/2007.

Distribution and habitat. Crooked Creek (Owyhee River basin), Barren Valley (Great Basin), plus new records from the Crooked Creek headspring and along the lower Owyhee River, southeastern Oregon ( Fig. 1 ). This species lives in springs and small streams. It was collected in association with Potamopyrgus antipodarum (USNM 1107069) at the mouth of Rinehart Creek.

Remarks. In an unpublished checklist, Taylor (1977) contended that the type locality of Fontelicella intermedia (= Pyrgulopsis intermedia ) may have been incorrectly attributed to Crooked Creek (Owyhee River drainage) instead of Crooked Creek (Deschutes River drainage) and consequently provided a new species name, Fontelicella malhorica , for the congener that lives in the headspring of the former stream. (Note that Taylor apparently changed his mind on this subject as he later stated that P. intermedia lives in Crooked Creek, Owyhee River drainage [ Taylor 1985:309–310].) In an unpublished report, Frest & Johannes (1995:198, 202) listed this nomen nudum (to which they applied a common name, “Malheur springsnail”) as a different species than P. intermedia and indicated that both of these snails live in Crooked Creek, Owyhee River drainage. Pyrgulopsis intermedia and P. sp. nov. (Malheur springsnail) have subsequently been listed in various conservation-related documents and publications (cited in the Introduction; also see Wisdom et al. 2003; Brown et al. 2007). Taylor’s (1977) manuscript name is not valid because his checklist does not constitute published work under ICZN Articles 8.1 and 9.7 and the only subsequent citation ( Frest & Johannes 1995) was also in an unpublished venue. (Also note in this context that the name was not accompanied by a description or definition.) There is no reason to suspect that Tryon (1865) made an error in reporting the type locality of P. intermedia as his types well conform to snails now living in Crooked Creek, Owyhee River drainage ( Hershler 1994). Snails (collected by Taylor) from Crooked Creek Spring (JFBM 20497, JFBM 20507, Fig. 10 A) conform morphologically to P. intermedia in all respects and our genetic studies also suggest that only one congener lives in Crooked Creek. Thus, there is no basis for recognizing the Malheur springsnail as a validly described and/or distinct species and this name therefore should be removed from conservation watch lists and other databases.

Snails from the newly reported localities are referable to P. intermedia based on their relatively large (> 3.3 mm), solid, ovate conic shell ( Fig. 10 A–D) with prominent spire; and details of penis shape and glandular ornament ( Fig. 11 A–B), particularly the short penial filament and medially positioned ventral gland. Samples from Crooked Creek (IP60) and the lower Owyhee River drainage (IP67, P217, P222, P223, P224) that were newly sequenced for this project were closely similar (0.2% divergence) to previously analyzed specimens from Crooked Creek (P1, P2) and Barren Valley (P4). The mean uncorrected sequence divergence within P. intermedia was quite low (0.2%), ranging from 0–0.8%.

The new records detailed herein extend the range of P. intermedia about 65 km north of its type locality area into the lower Owyhee River basin. It may be appropriate to reconsider the conservation status of this species in the light of this significant range extension.

Figures

FIGURE 1. Map showing the distributions of Pyrgulopsis species in southeastern Oregon. Arrows indicate previously documented localities; all others are newly reported herein. Some of the symbols refer to multiple, closely proximal localities.

FIGURE 10. P. intermedia (Tryon). A – D. Shells. Scale = 1.0 mm. A. JFBM 20507. B. USNM 1107071. C. USNM 1107076. D. USNM 1075362.

FIGURE 11. P. intermedia (Tryon). A – B. Penis, USNM 1075362. Scale bar = 0.5 mm. A. Dorsal surface. B. Ventral surface. Pd = penial duct, Pf = penial filament, Pg = penial gland, Pl = penial lobe, Tg = terminal gland, Vg = ventral gland.